A slot waveguide antenna is a type of antenna used for radar for high efficiency and high-power handling capability. To reach such high efficiency, a slot waveguide antenna array may be made of a metallic material, such as aluminum. A slot waveguide antenna is typically sensitive to assembly tolerances, meaning that small inaccuracies or gaps may negatively affect performance. A metallic waveguide slot antenna may require a costly manufacturing process to accurately machine the dimensions of the antenna and waveguide. A slot antenna called a substrate integrated waveguide (SIW) may be constructed of printed circuit board (PCB) material. SIW creates a waveguide within the substrate of the PCB. SIW antennae may suffer higher insertion loss than aluminum antennae, which may limit applications that could take advantage of SIW.